Controller for electric motors.



H. F. STRATTON. CONTROLLER FOR ELECTRIC MOTORS. APPLICATION FILED JULY17. 1913.

1,122,657. Patented De0.29,1914.

2 SHEETSSHEET 1.

WITNESSES H. F. STRAT TON.

CONTROLLER FOR ELECTRIC MOTORS APPLICATION FILED JULY 17,.1913.

Patented Dec. 29, 1914:.

INVENTOR I. BY

u ATTORNEY To all whom it may concern (UNITED STATES PATENT OFFICE.

nanny IE. STRA'ITON, OF CLEVELAND, 01:10, ASSIGNOR THE Etno'rmc CONTROLLER AND nauurnc'runme COMPANY, oFcLEyELAND, 01110, A oonronarronor 01-110.

CONTROLLER FOR ELECTRIC MOTORS.

Be it known that I, HARE-21F. S'rRatmoiI,

a citizen of the United States, residing at- Cleveland, in thecountyof Cuyaho'ga and State of Ohio, have inventednew and useful-Improvements in Controllers for Electric Motors, of whichthe following is a specification,

'- My invention relates 'to controllers for electric motors, particularly that type in.

which a part of the motor connections are made at the contacts of an'operator s switch and part are made'automatically at the -con-' tacts of magnetically-operated switches.

In the accompanying drawings, Figure 1 i is a diagrammatic View embodying one form of'my invention, and Fig, 2, is a similar view of a modification thereof.

-Referring first to Fig. 1', the motor is shown with thearmature A and-the shunt field -,Fl An operators switch is shown at -M. A service switch is shown at S for connectingthe system to a suitable source of cuit is shown at Rfl-R and R and this is theoperating windings of the switches are arranged to be connected in the motor cir- I cuit, and -wh1ch are adapted to remain open.

when thecurrent in the windings is above a predetermined-amount, and will operate to close their contacts when the current is reduced. The operating windings of the switches are indicated at C", C and (1 I The switch S is also providedwit h a shunt. i holding winding H, which is adapted to hold the switch closed after ithas been closed by its operatin winding, but thewinding H is not su cient tojclose. the

switch from its open position} The operators-switch has a series ofcon. tact fingers m to m9, arranged to engage the contacts M? when-the operators switch is moved to the position f. In like manner;

' they will engage the contacts M when the operators switch is moved to the position 7". 'VVhen. the operatorsswitch is at its central a position, as shown in the drawing, the contact fingers m and m engage, the contacts M and are connected thereby. When the opera-tor s switch is moved to the position f,

' the connections are so Ina-(lees to run the Application filed July 17, 1913.

Theresistance for .the motor cir-' SpecificationofLet tr sPatent. 4 P t t 2 ,i 4.

Serial No. 779,518.

motor in one direction, and 'when [it is moved to the position rthe connectionsare made to run the motor in the oppositedirection, the current being reversed in the motor armature. At the central position the armature is connected, in a closed or dynamic braking circuit through the contacts m and m of the operators switch, this circuit including a portion of the starting resistanceand the windings, of one or more of the resistance-controlling, switches. By this 4 arrangement the motor is made to comefto a quick stop when the controller is moved to the central position, the current being maintained at a high value in the motor cir:

cuit by the automatic cutting out of the starting resistance by the resistance-controlling switches. If it is desired to allow the motor to stop without-applying dynamic bra hing, the controller may be moved from position 7 or 1', to a positlonintermediate;

these positions and the central position,

whereupon'the motor circuit 'is-openedat tion of the load it is driving. i

I will now describe the operation of the controller." When the switch S is closed, the shunt 'field F is energized through'the wires the'n'iotor will come to rest due to the fricl and 2. "Upon movinentof the operators switch. to the position f, the motor cir- 'the contacts of the operators switch, and

cuit is, as follows; .From the positive through the wire 3, the contact finger m,

the contacts M, the contact finger m the wire 4,. the motor armature A, the wire 5, the winding C, the resistances R, R and R the wire, the contact finger 970*, the contacts M, the contact finger m and-the wire 7 to they negative. in the forward direction and is brought up to speed by the cutting out of the resistancesR, R and R by means of the resistance switches S, 8*, and S The. switch S in closing cuts out the resistance R and ener--'- gizes the winding C the switch S in clos- 1 ing cuts'out the, resistance R and energizes The mbtor startsthe winding C the switch S 'in closing cuts out the resistance R -and dee'ner'gizes the windings C, 'C and C, the current-in the motor circultnow flowing" from the ice armature through the, wire 8, the contacts 1' of the switch S and the wire 6,. instea ilof, through thepreviouslytraced path through: i

the resistances R, R and R The switch ft" is now held closedby its holding winds ing -H, whose circuit is from the positive through the wire 3,- the contact finger m', the contacts M, the contact finger m, the wire 9, the winding H, the contacts of the switch S the wire 6, and the contactfingers m and m and the wire 7 to the negative. If it is now desired to stop the motor quickly, the operators switch is moved to the central position, whereupon the motor is disconnected from the source of supply -namlc braking.

at the contacts of the operators switch and a dynamic braking circuit is closed 'including the contact fingers m and m of the operators switch. This circuit is as follows: F rom the armature A through the wire 4, the contact finger m the contact M the contact finger m, the wire 10 to a -va lue, whereupon the resistance R is cut out and the current now flows through all of the windings 0, C and C The armature is quickly brought to rest, and when the current ceases, the switches SQ), and S drop open and the motor 1s ready to be started again.

If the operators switch is moved to the position 1', current flows through the'wire 3, the contact finger m the contacts M the contact finger m the wire 6, the resistances R R and R, the winding C, the wire 5,

the armature A, the I wire 4, the contact finger m contacts M the contact finger m, and the wire 7 to the negative. The current is reversed through the armature circuit, thus causing the motor to run in the opposite direction. The switches S, S S will proceed to cut out the starting resistance, as before described, to bring the motor up to speed. The current through the holding winding H has also been reversed, so that the magnetism produced by this winding will correspond to the magnetism produced by the winding C The circuit through. the

winding H is now as follows: From the positive through the wire 3, the contactfinger m the contacts M the finger m, the wire 6, the contacts of the switch S the winding H, the wire 9, the contact finger M, the contacts M the contact fin er m and the wire 7 to the ne ative.

Upon movement of the operators switch to the central position the dynamic braking circuit will be closed as before described, but thecurrent will flow in a circuit beginning at the left-hand brush of the armature A, and will goby way of the wire 5, the winding C, the resistances R and R the wire 10, the contact fingers m -and m and the wire 4 to the right-hand brush'of the armature. The slowing down of the motor is accomplished by movement of the operators switch to the central position from either of the running positions, and the same set of resistance switches control the current in the motor circuit whether the motor is started in the forward or reverse direction, or Whether it is stopped by dy- Rcferring to Fig. 2, in which the operators switch D is arranged to run the motor in one direction only, the contact fingers m to m have the same arrangement as in Fig.

l, and the contacts D are the same as the contacts M. The contacts D however, are changed to make the proper connections for bringing the motor to rest when the controller is moved to the position d after the motor has been running as the result of the operators switch having been moved to the position 7'. When the operators sWitchDis moved to the position f the motor is started in the same manner as described under Fig. 1 When it is desired to stop the motor the operator may move the operators switch to the central position and cut the motor oil from the line, allowing it to stop by its friction load, but if he wishes to stop the motor quickly, the operators switch is moved to the' position d, whereupon the motor circuit will be as follows: From the right-hand'brush of the armature A, the wire a, the contact finger m the contact D the contact finger m, the wire 10, the resistances R and R, the winding C of the switch S, and the Wire 5 to the left-hand brush of the armature. I

The dynamic braking circuit thus establishcd causes the retardation of the armature, and the current in this circuit is maintained at a high value by the cutting out of the resistances R and R" at the closure of the switches i" and S When the switch S closes, the winding C is energized, causing the switch S to close.

In order that the holding winding H may produce a magnetism in the switch frame corresponding to that produced by the winding 0 its circuit is reversed through the contacts of the operators switch and current lilows in it as follows: From the positive through the wire 3, the contact finger m, the contacts D the contact finger m, the wire 6, the contacts of the switch S, the winding H, the wire 9, the contact finger m, the contacts I), the wire 7 to the negative. The switch S will remain closed as long as the operator holds the operators switch" in the position the contact finger m and i '0 and the dynamic braking circuit will be containing means for connecting the motor to the source in series with the said winding for accelerating the motor and for connect ing the motor and the said winding in a dynamic braking circuit to retard the motor.

2. In a motor control system, a motor armature, a resistance. for controlling the current therein, a switch for the resistance, an operating winding therefor energized by current through the armature, and an operators switch for connecting the motor armature to a source of supply in series with the resistance and the said switch winding and for connecting the motor armature, the resistance, and the switch winding in a dynamic braking circuit.

3. In a motor control svstem, a motor armature, a circuit therefor, resistance in the circuit,a series of switches for controlling the resistance, operating windings for the switches energized by current through the motor armature, a shunt holding windi. for at least the last switch of the series, and an operators switch for reversing the current in the motor armature, the said operating windings, and the said shunt holding winding.

4. In a motor control system, a source of supply, a motor armature, a resistance, a

series of magnetically-operated switches for cutting out said resistance, operating windings therefor energized by currentw through the motor armature, a shunt holding winding for the last switch of the series, connections whereby the last switch in closing deenergizes its operating winding,

and an operators switch for connecting the motor armature to the source in series with the resistance and the said operating wind ings, for disconnecting the source and for reversing the current in the armature, resistanee,,opcrating windings, and shunt holding to winding.

5. In a motor control system, a source 01" supply, a motor armature, a resistance, a series of magnetically-operated switches for cutting out the said resistance, operating windings therefor energized by current through the motor armature, a shunt holding winding for the last switch of the series, connections whereby the last switch in closing deenergizes' its operating winding, and c0 an operators switch for connecting the 'motor armature to the source 1n series with the resistance and the said operating windings, for disconnecting the source, for connecting the armature, resistance, and operatingwindings in a dynamic braking circuit, and for reversing the current in the said shunt holding winding.

Signed at Cleveland, Ohio, this 15th day of July, A. D. 1913.

HARRY F. STRATTON.

Witnesses: i

J. H. HALL, W. M. DIEMER- 

